Sugar as a tool for asymmetric synthesis: Some effective approaches

Kiichiro Totani, Ken Ichi Takao, Kin Ichi Tadano

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

Highly diastereoselective carbon-carbon bond-forming reactions achieved on a variety of sugar templates were found. For example, methyl 6-deoxy-2,3-di-O-(t-butyldimethylsilyl)-α-D-glucopyranoside can serve as a versatile and effective chiral auxiliary. Namely, the 1,4-addition reactions to its 4-O-crotonyl ester of some carbon nucleophiles or alkyl radicals proceeded highly diastereoselectively to afford the corresponding adducts. The alkylation of the enolate generated from its 4-O-propionyl ester afforded the α-alkylated product with a useful level of stereoselectivity. Furthermore, the Diels-Alder reaction of its 4-O-acryloyl ester with cyclopentadiene afforded an endo-adduct stereoselectively. In the case of the 1,3-dipolar cycloaddition of the acryloyl ester, again the cycloadduct was obtained highly stereoselectively. Some other types of sugar templates prepared from methyl α-D-glucopyranoside, α-D-mannopyranoside and α-D- galactopyranoside were explored to verify their ability to function as chiral templates. In some cases, these templates afforded complementary results in the sense of diastereoselectivity. Methodologies for the removal of the sugar template from the products were developed. 1 Introduction 2 Background 3 Our Approach 4 The Sugar Templates 5 Stereoselective Ionic Carbon-Carbon Bond-Forming Reactions 5.1 1,4-Addition Reactions of Organometallic Species to an αβ-Unsaturated Ester Moiety in the Sugar Templates 5.2 α-Alkylations of a Propionyl Ester Enolate Formed in the Sugar Templates with Alkyl Halides 5.3 One-Pot Tandem 1,4-Addition/α-Alkylation Reactions Applied to an α,β-Unsaturated Ester Moiety in the Sugar Templates 5.4 1,4-Addition Reactions of an Enolate Formed in the Sugar Template to Methyl Crotonate: A Practical Total Synthesis of the Insect Pheromone (-)-Lasiol 6 1,4-Addition Reactions of an Alkyl Radical to a Crotonyl Ester in the Sugar Templates 7 Stereoselective Pericyclic Reactions 7.1 Diels-Alder Reactions of an Acryloyl Ester in the Sugar Templates 7.2 1,3-Dipolar Cycloadditions of a Nitrile Oxide to an Acryloyl Ester in the Sugar Template 8 Dihydroxylation Reactions of an α,β-Unsaturated Ester in the Sugar Templates 9 Conclusions.

Original languageEnglish
Pages (from-to)2066-2080
Number of pages15
JournalSynlett
Issue number12
DOIs
Publication statusPublished - 2004 Oct 1

Keywords

  • Asymmetric synthesis
  • Carbohydrates
  • Chiral auxiliaries
  • Michael additions
  • Pericyclic reactions

ASJC Scopus subject areas

  • Organic Chemistry

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